The “green” incarnation of travel, called ecotourism, mandates that travelers minimize their cultural, economic, and environmental impacts as much as possible to promote sustainability. But while there are thousands of hotels worldwide that promote themselves as “green”, many of them are only partially fulfilling these requirements – they might not be wasting energy, but are paying locals at near-slave wages, or funneling money out of the local economy.

Whole Travel, a new site that launches tonight, is looking to keep these hotels honest while promoting the concept of sustainable travel. The site assigns each hotel with a score based on its environmental, cultural, and economic impacts, as well as its “customer interaction”, or how well it teaches visitors about the issues that affect their destination.

To receive a score, hotels first self-assign a rating based on how well they think they fare in each category. Whole Travel CEO Matthew Davie acknowledges that these scores will be biased, but believes that submitting a misleading score would actually hurt hotels in the long run, as readers of the site would be able to tag them as dishonest and discourage prospective customers. However, the site isn’t relying on good faith alone – it is also working with local non-profits around the world to verify rating for hotels in their regions. The site is also working with international non-profits like Sustainable Travel International, which has similar goals but is based on a “badge” system that hotels need to pay for to become accredited as Green.

Besides the new hotel rating system, Whole Travel also includes a number of more standard features that you’d expect on a travel site. Users can search for hotels using descriptive keywords rather than location names (you could search for “relaxing” for a list of locations that fit the bill). The site also includes standard lists of hotel pricing and links to Kayak to book flights and hotels.

As a travel site Whole Travel isn’t doing anything new – you can aggregate hotel listings on countless other places across the web. But its “green” hotel rating system could prove both very popular and very lucrative, provided the site is able to establish credibility. And with partnerships with major hotel chains already in the works, the company may not be far from painting the world – and its pocketbook – green.